It is all about consciusness and education, hydroelectrical generation is nowadays not the same thing it used to be, http://www.bbc.com/future/story/20150610-blue-energy-how-mixing-water-can-create-electricity the chemical natural reaction when a river touch the sea(salty water) is a huge source of energy and super clean process.
There will always be the human insterests that slow down these initiatives, but knowledge is power, and if we have in our hand to teach, at least those around us, we will be contribuiting to a healthier enviroment and we will be surrounded by responsable people.
free energy has existed for 100 years... we still pay for energy, so I wouldnt be so optimistic.
Have you heard about sonoluminescence?
If there is little or no profits, corporations are not interested. Simple, That is why earthly destruction is pretty advanced as we speak. I blog about it quite much.
There is no such thing as "free" energy. It all comes from somewhere. Even if we were to pull a Tesla and grab energy from the ionosphere, it would still not be free. It would have to be harvested, stored/transported etc...